1. Field of the Invention
The invention relates to an exhaust gas recirculation device for an engine, provided with a mechanism for recirculating a portion of exhaust gas to the suction side of the engine.
2. Background Art
Conventionally, there is a well-known exhaust gas recirculation device (hereinafter, “EGR”) for an engine, which is provided with a mechanism connecting an exhaust flow passage to a suction flow passage so as to recirculate exhaust gas to the suction side of the engine. The EGR mechanism recirculates a portion of gas exhausted from the engine to the suction flow passage so as to reduce the temperature of combusted gas in the cylinder, thereby reducing NOx.
To construct the EGR mechanism, as disclosed Japanese Laid-open Gazette No.
Hei 5-18323, for instance, an EGR passage is formed between the suction flow passage and the exhaust flow passage so that the exhaust flow passage communicates to the suction flow passage via the EGR passage so as to recirculate exhaust gas.
However, in this recirculation device for an engine, the EGR mechanism is complicated and expensive because the EGR mechanism is a pipe disposed between the suction flow passage and the exhaust flow passage.